The invention relates to a blade of a turbo machine, in particular a gas turbine.
Modern gas turbines, particularly aircraft engines, must do justice to the highest requirements with respect to reliability, weight, performance, cost-effectiveness and service life. In the development of gas turbines, the material selection, the search for new, suitable materials as well the search for new fabrication methods, among other things, play a crucial role. The most important materials that are used nowadays for aircraft engines or other turbomachines are titanium alloys and high-strength steels. The high-strength steels are used for shaft parts, transmission parts, the compressor housing and the turbine housing. Titanium alloys are typical materials for compressor parts. Nickel alloys are suitable for the hot turbine parts.
As a rule, gas turbines encompass several rotating rotor blades as well as several stationary guide vanes, whereby the rotor blades rotate along with a rotor, and whereby the rotor blades as well as the guide vanes are enclosed in a stationary housing. To increase performance, it is important for all components and subsystems to be optimized. To increase the degree of efficiency of gas turbines, it is desirable to design particularly the rotor blades as well as the guide vanes to be lighter, i.e., having a lower weight. However, light materials have relatively low ductility and furthermore are relatively brittle, whereby in the case of high localized stresses, which are common on the blades, an overload and thus failure of the materials or of the blades can arise. As a result, it has not been possible in practice until now to fabricate the blades from light materials, whereby ultimately the degree of efficiency and therefore increased performance of the gas turbines are limited.
Thus, the present invention is based on the objective of creating a novel blade of a turbomachine.
According to the invention, the, or each, fastening section has a core region which is made of a relatively brittle and relatively light material and is embedded in an encasing region made of a material having relatively high ductility.
The invention makes it possible to use light as well as brittle materials for fabricating blades. According to the invention, the core region of the fastening section of the blade is manufactured of the light as well as brittle material, whereby the core region is embedded in an encasing region, which is fabricated of a material having high ductility. Due to the encasing of the core region, it is possible to avoid overloads on contact surfaces between an outer contour of the fastening section and an inner contour of a locating section for the fastening section itself in the case of high localized loads.
By using light as well as brittle materials for the blades, it is possible for the first time with the present invention to realize enormous savings in terms of weight. This results in an optimization of the degree of efficiency and thus in an increase in performance.